I can see that there are reasons to do it when the dogs are bred as guard dogs. I see none for companion dogs however.
In the case of a Doberman, this is not a guard dog. Dobermans are referred to and were bred as
personal protection dogs. There is a difference. They don't go out in some junk yard all by themselves all night and guard rusty old cars. They stay glued to their family or person and stand by, prepared to protect if need be. They do this naturally without any specific protection training.
First and formost they are a companion. If they are not raised in very close proximity with their owner, raised in a loving, companionable, bonded, close way, they will not have a very good reason to protect their people. Dogs who are mistreated, neglected.... or don't have a companionable relationdhip with their owner are not good, reliable protection dogs. So, I don't understand the distinction that has been made by a few here.....of a protection dog and a companion dog. They are one in the same. They are both.
My Doberman, Lyric is the love of my life. I love this dog so much. And he is sooooo "into" me. He is my constant, velcro companion. We work on obedience and agility, go on hikes together, go everywhere together. He is my baby and sits his 95 LBS on my lap. LOL (or tries to) There's usually one leg or his chin on me. We are very, closely bonded, a closer bond than I've ever had with a dog, even though I loved all my dogs. He has also shown his ability to protect me on a few occasions. He is always ready and alert. He can't lie down in the evening and let sounds outside slip by him. He's up in a flash, muscled up at every sound. If I get up from the couch, occasionally he'll stay put, but more often, he'll follow me where I'm going. I can't go out on the deck by myself and close him inside with me out there to have a cigerette without his whining and "neeeeeeeeding" to be out there with me. The minute I reach for my cigerette pack, that dog is on his feet quicker than you can blink an eye.
So, in other words, Lyric is my loving companion but he is also a protection/working dog. If he gets into it with someone or some wild animal, he is built compactly, squarely without anything combersome or anything hanging off of him to get in the way or get hurt. He hears things and knows quite accurately where the sound is coming from, something a lot of dogs are not so good at. (pinpointing direction of sound)
Dobermans are extremely atheletic, agile, quick, very fast runners. (Greyhound in their background)They are high energy and will not back down. They will not avoid hurting themselves if they need to do something in the line of duty. They're pushy, demanding and persistant. These traits contribute to the higher possibility of them getting themselves into a fix or getting hurt.
Yes, the ears are for looks too. These dogs look sharp. They were bred to be sharp, aggressive (when needed) They were not designed to look soft, fluffy and tolerant like a hound dog. Looking sharp, with those upright ears and looking the way their reputation has it, prevents a lot of mistakes from people. When an intruder or an attacker sees a Doberman, they tend to change their mind about what they may have been planning. Preventing contact with a bad guy is always the better choice.
Looking like a Doberman also prevents stupid people from running up to your dog, thinking it's an outgoing, friendly hound or hunting dog. They are not outgoing. Dobermans are reserved around stragers, not enthralled with meeting them, although will stand nicely and accept a pat. (that's the way they're suppose to be....it's how Lyric is too) But they would not appreciate the way some people act around dogs, the stupid ones. If a Doberman looks like a Doberman, people will tend to be more respectful or careful.
There are all kinds of good reasons for cropping and docking besides looking pretty.